The present invention relates to a combustion chamber for a gas turbine engine, more particularly such a structure in which the positions of the primary oxidizer intake passageways are variable relative to an end of the combustion chamber.
Known combustion chambers for gas turbine engines have numerous oxidizer intake orifices which enable oxidizer to enter the interior of the combustion chamber to enhance combustion of the fuel/oxidizer mixture within the combustion chamber. A distinction must be made between the primary oxidizer intake orifices which admit oxidizer which is essential to the actual combustion of the fuel/oxidizer mixture within the combustion chamber, and dilution oxidizer intake orifices through which oxidizer is admitted to the combustion chamber to dilute the combustion gases and to homogenize the temperature of the burnt gases, as well as to properly adjust the gas flow to feed the gas turbine located at the exit of the combustion chamber.
The primary oxidizer intake orifices must accommodate vastly different operational modes of the gas turbine engine combustion chamber. When the gas turbine is operated at low power, the dwell time of the combustion gases within the intake zone of the oxidizer fed into the combustion chamber around the fuel injecters, as well as that fed through the intake orifices of the primary oxidizer, must be sufficiently long so that the combustion stability is enhanced and the polluting emissions of carbon monoxide (CO) and unburnt hydrocarbons (CHx) can be reduced. Under full power operating conditions, the dwell time of the combustion gases within the intake zone must be shortened in order to reduce the polluting emissions of nitrogen oxide (NOx). Known combustion chamber designs have been unable to fully meet these conflicting requirements.